A shoe store developed the following estimated regression equation relating sales to inventory investment and advertising expenditures. ŷ = 21 + 10x, + 7x2 %D where X1 inventory investment ($1,000s)...

Extracted text: A shoe store developed the following estimated regression equation relating sales to inventory investment and advertising expenditures. ŷ = 21 + 10x, + 7x2 %D where X1 inventory investment ($1,000s) advertising expenditures ($1,000s) X2 sales ($1,000s). y = (a) Predict the sales (in dollars) resulting from a $15,000 investment in inventory and an advertising budget of $10,000. (b) Interpret b1 and b, in this estimated regression equation. 2. Sales can be expected to increase by $ for every dollar increase in inventory investment when advertising expenditure is held constant. Sales can be expected to increase by $ for every dollar increase in advertising expenditure when inventory investment is held constant.